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Implement Chalk variable kinds

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This means we need to keep track of the kinds (general/int/float) of variables
in `Canonical`, which requires some more ceremony. (It also exposes some places
where we're not really dealing with canonicalization correctly -- another thing
to be cleaned up when we switch to using Chalk's types directly.)

Should fix the last remaining issue of #2534.
This commit is contained in:
Florian Diebold 2020-06-28 21:17:27 +02:00 committed by Florian Diebold
parent 4a19d5954a
commit d5d485ef92
8 changed files with 140 additions and 71 deletions
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10
crates/ra_hir/src/code_model.rs
View file

@ -1187,7 +1187,7 @@ impl Type {
None => return false,
};
let canonical_ty = Canonical { value: self.ty.value.clone(), num_vars: 0 };
let canonical_ty = Canonical { value: self.ty.value.clone(), kinds: Arc::new([]) };
method_resolution::implements_trait(
&canonical_ty,
db,
@ -1211,7 +1211,7 @@ impl Type {
self.ty.environment.clone(),
hir_ty::Obligation::Trait(trait_ref),
),
num_vars: 0,
kinds: Arc::new([]),
};
db.trait_solve(self.krate, goal).is_some()
@ -1286,7 +1286,7 @@ impl Type {
pub fn autoderef<'a>(&'a self, db: &'a dyn HirDatabase) -> impl Iterator<Item = Type> + 'a {
// There should be no inference vars in types passed here
// FIXME check that?
let canonical = Canonical { value: self.ty.value.clone(), num_vars: 0 };
let canonical = Canonical { value: self.ty.value.clone(), kinds: Arc::new([]) };
let environment = self.ty.environment.clone();
let ty = InEnvironment { value: canonical, environment };
autoderef(db, Some(self.krate), ty)
@ -1327,7 +1327,7 @@ impl Type {
// There should be no inference vars in types passed here
// FIXME check that?
// FIXME replace Unknown by bound vars here
let canonical = Canonical { value: self.ty.value.clone(), num_vars: 0 };
let canonical = Canonical { value: self.ty.value.clone(), kinds: Arc::new([]) };
let env = self.ty.environment.clone();
let krate = krate.id;
@ -1358,7 +1358,7 @@ impl Type {
// There should be no inference vars in types passed here
// FIXME check that?
// FIXME replace Unknown by bound vars here
let canonical = Canonical { value: self.ty.value.clone(), num_vars: 0 };
let canonical = Canonical { value: self.ty.value.clone(), kinds: Arc::new([]) };
let env = self.ty.environment.clone();
let krate = krate.id;

15
crates/ra_hir_ty/src/autoderef.rs
View file

@ -37,7 +37,7 @@ pub(crate) fn deref(
ty: InEnvironment<&Canonical<Ty>>,
) -> Option<Canonical<Ty>> {
if let Some(derefed) = ty.value.value.builtin_deref() {
Some(Canonical { value: derefed, num_vars: ty.value.num_vars })
Some(Canonical { value: derefed, kinds: ty.value.kinds.clone() })
} else {
deref_by_trait(db, krate, ty)
}
@ -68,8 +68,8 @@ fn deref_by_trait(
// Check that the type implements Deref at all
let trait_ref = TraitRef { trait_: deref_trait, substs: parameters.clone() };
let implements_goal = super::Canonical {
num_vars: ty.value.num_vars,
let implements_goal = Canonical {
kinds: ty.value.kinds.clone(),
value: InEnvironment {
value: Obligation::Trait(trait_ref),
environment: ty.environment.clone(),
@ -81,7 +81,7 @@ fn deref_by_trait(
// Now do the assoc type projection
let projection = super::traits::ProjectionPredicate {
ty: Ty::Bound(BoundVar::new(DebruijnIndex::INNERMOST, ty.value.num_vars)),
ty: Ty::Bound(BoundVar::new(DebruijnIndex::INNERMOST, ty.value.kinds.len())),
projection_ty: super::ProjectionTy { associated_ty: target, parameters },
};
@ -89,7 +89,8 @@ fn deref_by_trait(
let in_env = InEnvironment { value: obligation, environment: ty.environment };
let canonical = super::Canonical { num_vars: 1 + ty.value.num_vars, value: in_env };
let canonical =
Canonical::new(in_env, ty.value.kinds.iter().copied().chain(Some(super::TyKind::General)));
let solution = db.trait_solve(krate, canonical)?;
@ -110,7 +111,7 @@ fn deref_by_trait(
// assumptions will be broken. We would need to properly introduce
// new variables in that case
for i in 1..vars.0.num_vars {
for i in 1..vars.0.kinds.len() {
if vars.0.value[i - 1] != Ty::Bound(BoundVar::new(DebruijnIndex::INNERMOST, i - 1))
{
warn!("complex solution for derefing {:?}: {:?}, ignoring", ty.value, solution);
@ -119,7 +120,7 @@ fn deref_by_trait(
}
Some(Canonical {
value: vars.0.value[vars.0.value.len() - 1].clone(),
num_vars: vars.0.num_vars,
kinds: vars.0.kinds.clone(),
})
}
Solution::Ambig(_) => {

55
crates/ra_hir_ty/src/infer/unify.rs
View file

@ -9,7 +9,7 @@ use test_utils::mark;
use super::{InferenceContext, Obligation};
use crate::{
BoundVar, Canonical, DebruijnIndex, GenericPredicate, InEnvironment, InferTy, Substs, Ty,
TypeCtor, TypeWalk,
TyKind, TypeCtor, TypeWalk,
};
impl<'a> InferenceContext<'a> {
@ -86,10 +86,20 @@ where
}
fn into_canonicalized<T>(self, result: T) -> Canonicalized<T> {
Canonicalized {
value: Canonical { value: result, num_vars: self.free_vars.len() },
free_vars: self.free_vars,
}
let kinds = self
.free_vars
.iter()
.map(|v| match v {
// mapping MaybeNeverTypeVar to the same kind as general ones
// should be fine, because as opposed to int or float type vars,
// they don't restrict what kind of type can go into them, they
// just affect fallback.
InferTy::TypeVar(_) | InferTy::MaybeNeverTypeVar(_) => TyKind::General,
InferTy::IntVar(_) => TyKind::Integer,
InferTy::FloatVar(_) => TyKind::Float,
})
.collect();
Canonicalized { value: Canonical { value: result, kinds }, free_vars: self.free_vars }
}
pub(crate) fn canonicalize_ty(mut self, ty: Ty) -> Canonicalized<Ty> {
@ -131,26 +141,41 @@ impl<T> Canonicalized<T> {
ty
}
pub fn apply_solution(&self, ctx: &mut InferenceContext<'_>, solution: Canonical<Vec<Ty>>) {
pub fn apply_solution(&self, ctx: &mut InferenceContext<'_>, solution: Canonical<Substs>) {
// the solution may contain new variables, which we need to convert to new inference vars
let new_vars = Substs((0..solution.num_vars).map(|_| ctx.table.new_type_var()).collect());
let new_vars = Substs(
solution
.kinds
.iter()
.map(|k| match k {
TyKind::General => ctx.table.new_type_var(),
TyKind::Integer => ctx.table.new_integer_var(),
TyKind::Float => ctx.table.new_float_var(),
})
.collect(),
);
for (i, ty) in solution.value.into_iter().enumerate() {
let var = self.free_vars[i];
// eagerly replace projections in the type; we may be getting types
// e.g. from where clauses where this hasn't happened yet
let ty = ctx.normalize_associated_types_in(ty.subst_bound_vars(&new_vars));
let ty = ctx.normalize_associated_types_in(ty.clone().subst_bound_vars(&new_vars));
ctx.table.unify(&Ty::Infer(var), &ty);
}
}
}
pub fn unify(ty1: &Canonical<Ty>, ty2: &Canonical<Ty>) -> Option<Substs> {
pub fn unify(tys: &Canonical<(Ty, Ty)>) -> Option<Substs> {
let mut table = InferenceTable::new();
let num_vars = ty1.num_vars.max(ty2.num_vars);
let vars =
Substs::builder(num_vars).fill(std::iter::repeat_with(|| table.new_type_var())).build();
let ty1_with_vars = ty1.value.clone().subst_bound_vars(&vars);
let ty2_with_vars = ty2.value.clone().subst_bound_vars(&vars);
let vars = Substs(
tys.kinds
.iter()
// we always use type vars here because we want everything to
// fallback to Unknown in the end (kind of hacky, as below)
.map(|_| table.new_type_var())
.collect(),
);
let ty1_with_vars = tys.value.0.clone().subst_bound_vars(&vars);
let ty2_with_vars = tys.value.1.clone().subst_bound_vars(&vars);
if !table.unify(&ty1_with_vars, &ty2_with_vars) {
return None;
}
@ -162,7 +187,7 @@ pub fn unify(ty1: &Canonical<Ty>, ty2: &Canonical<Ty>) -> Option<Substs> {
}
}
Some(
Substs::builder(ty1.num_vars)
Substs::builder(tys.kinds.len())
.fill(vars.iter().map(|v| table.resolve_ty_completely(v.clone())))
.build(),
)

22
crates/ra_hir_ty/src/lib.rs
View file

@ -662,13 +662,27 @@ impl TypeWalk for GenericPredicate {
/// Basically a claim (currently not validated / checked) that the contained
/// type / trait ref contains no inference variables; any inference variables it
/// contained have been replaced by bound variables, and `num_vars` tells us how
/// many there are. This is used to erase irrelevant differences between types
/// before using them in queries.
/// contained have been replaced by bound variables, and `kinds` tells us how
/// many there are and whether they were normal or float/int variables. This is
/// used to erase irrelevant differences between types before using them in
/// queries.
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct Canonical<T> {
pub value: T,
pub num_vars: usize,
pub kinds: Arc<[TyKind]>,
}
impl<T> Canonical<T> {
pub fn new(value: T, kinds: impl IntoIterator<Item = TyKind>) -> Self {
Self { value, kinds: kinds.into_iter().collect() }
}
}
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
pub enum TyKind {
General,
Integer,
Float,
}
/// A function signature as seen by type inference: Several parameter types and

32
crates/ra_hir_ty/src/method_resolution.rs
View file

@ -2,7 +2,7 @@
//! For details about how this works in rustc, see the method lookup page in the
//! [rustc guide](https://rust-lang.github.io/rustc-guide/method-lookup.html)
//! and the corresponding code mostly in librustc_typeck/check/method/probe.rs.
use std::sync::Arc;
use std::{iter, sync::Arc};
use arrayvec::ArrayVec;
use hir_def::{
@ -17,7 +17,8 @@ use rustc_hash::{FxHashMap, FxHashSet};
use super::Substs;
use crate::{
autoderef, db::HirDatabase, primitive::FloatBitness, utils::all_super_traits, ApplicationTy,
Canonical, DebruijnIndex, InEnvironment, TraitEnvironment, TraitRef, Ty, TypeCtor, TypeWalk,
Canonical, DebruijnIndex, InEnvironment, TraitEnvironment, TraitRef, Ty, TyKind, TypeCtor,
TypeWalk,
};
/// This is used as a key for indexing impls.
@ -377,7 +378,7 @@ fn iterate_method_candidates_with_autoref(
return true;
}
let refed = Canonical {
num_vars: deref_chain[0].num_vars,
kinds: deref_chain[0].kinds.clone(),
value: Ty::apply_one(TypeCtor::Ref(Mutability::Shared), deref_chain[0].value.clone()),
};
if iterate_method_candidates_by_receiver(
@ -393,7 +394,7 @@ fn iterate_method_candidates_with_autoref(
return true;
}
let ref_muted = Canonical {
num_vars: deref_chain[0].num_vars,
kinds: deref_chain[0].kinds.clone(),
value: Ty::apply_one(TypeCtor::Ref(Mutability::Mut), deref_chain[0].value.clone()),
};
if iterate_method_candidates_by_receiver(
@ -612,18 +613,19 @@ pub(crate) fn inherent_impl_substs(
// we create a var for each type parameter of the impl; we need to keep in
// mind here that `self_ty` might have vars of its own
let vars = Substs::build_for_def(db, impl_id)
.fill_with_bound_vars(DebruijnIndex::INNERMOST, self_ty.num_vars)
.fill_with_bound_vars(DebruijnIndex::INNERMOST, self_ty.kinds.len())
.build();
let self_ty_with_vars = db.impl_self_ty(impl_id).subst(&vars);
let self_ty_with_vars =
Canonical { num_vars: vars.len() + self_ty.num_vars, value: self_ty_with_vars };
let substs = super::infer::unify(&self_ty_with_vars, self_ty);
let mut kinds = self_ty.kinds.to_vec();
kinds.extend(iter::repeat(TyKind::General).take(vars.len()));
let tys = Canonical { kinds: kinds.into(), value: (self_ty_with_vars, self_ty.value.clone()) };
let substs = super::infer::unify(&tys);
// We only want the substs for the vars we added, not the ones from self_ty.
// Also, if any of the vars we added are still in there, we replace them by
// Unknown. I think this can only really happen if self_ty contained
// Unknown, and in that case we want the result to contain Unknown in those
// places again.
substs.map(|s| fallback_bound_vars(s.suffix(vars.len()), self_ty.num_vars))
substs.map(|s| fallback_bound_vars(s.suffix(vars.len()), self_ty.kinds.len()))
}
/// This replaces any 'free' Bound vars in `s` (i.e. those with indices past
@ -683,15 +685,15 @@ fn generic_implements_goal(
trait_: TraitId,
self_ty: Canonical<Ty>,
) -> Canonical<InEnvironment<super::Obligation>> {
let num_vars = self_ty.num_vars;
let mut kinds = self_ty.kinds.to_vec();
let substs = super::Substs::build_for_def(db, trait_)
.push(self_ty.value)
.fill_with_bound_vars(DebruijnIndex::INNERMOST, num_vars)
.fill_with_bound_vars(DebruijnIndex::INNERMOST, kinds.len())
.build();
let num_vars = substs.len() - 1 + self_ty.num_vars;
kinds.extend(iter::repeat(TyKind::General).take(substs.len() - 1));
let trait_ref = TraitRef { trait_, substs };
let obligation = super::Obligation::Trait(trait_ref);
Canonical { num_vars, value: InEnvironment::new(env, obligation) }
Canonical { kinds: kinds.into(), value: InEnvironment::new(env, obligation) }
}
fn autoderef_method_receiver(
@ -704,9 +706,9 @@ fn autoderef_method_receiver(
if let Some(Ty::Apply(ApplicationTy { ctor: TypeCtor::Array, parameters })) =
deref_chain.last().map(|ty| &ty.value)
{
let num_vars = deref_chain.last().unwrap().num_vars;
let kinds = deref_chain.last().unwrap().kinds.clone();
let unsized_ty = Ty::apply(TypeCtor::Slice, parameters.clone());
deref_chain.push(Canonical { value: unsized_ty, num_vars })
deref_chain.push(Canonical { value: unsized_ty, kinds })
}
deref_chain
}

18
crates/ra_hir_ty/src/tests/traits.rs
View file

@ -3029,3 +3029,21 @@ fn infer_dyn_fn_output() {
"###
);
}
#[test]
fn variable_kinds() {
check_types(
r#"
trait Trait<T> { fn get(self, t: T) -> T; }
struct S;
impl Trait<u128> for S {}
impl Trait<f32> for S {}
fn test() {
S.get(1);
//^^^^^^^^ u128
S.get(1.);
//^^^^^^^^ f32
}
"#,
);
}

16
crates/ra_hir_ty/src/traits.rs
View file

@ -1,5 +1,5 @@
//! Trait solving using Chalk.
use std::{panic, sync::Arc};
use std::sync::Arc;
use chalk_ir::cast::Cast;
use hir_def::{
@ -8,7 +8,7 @@ use hir_def::{
use ra_db::{impl_intern_key, salsa, CrateId};
use ra_prof::profile;
use crate::{db::HirDatabase, DebruijnIndex};
use crate::{db::HirDatabase, DebruijnIndex, Substs};
use super::{Canonical, GenericPredicate, HirDisplay, ProjectionTy, TraitRef, Ty, TypeWalk};
@ -190,15 +190,7 @@ fn solution_from_chalk(
solution: chalk_solve::Solution<Interner>,
) -> Solution {
let convert_subst = |subst: chalk_ir::Canonical<chalk_ir::Substitution<Interner>>| {
let value = subst
.value
.iter(&Interner)
.map(|p| match p.ty(&Interner) {
Some(ty) => from_chalk(db, ty.clone()),
None => unimplemented!(),
})
.collect();
let result = Canonical { value, num_vars: subst.binders.len(&Interner) };
let result = from_chalk(db, subst);
SolutionVariables(result)
};
match solution {
@ -222,7 +214,7 @@ fn solution_from_chalk(
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct SolutionVariables(pub Canonical<Vec<Ty>>);
pub struct SolutionVariables(pub Canonical<Substs>);
#[derive(Clone, Debug, PartialEq, Eq)]
/// A (possible) solution for a proposed goal.

43
crates/ra_hir_ty/src/traits/chalk/mapping.rs
View file

@ -17,7 +17,7 @@ use crate::{
primitive::{FloatBitness, FloatTy, IntBitness, IntTy, Signedness},
traits::{builtin, AssocTyValue, Canonical, Impl, Obligation},
ApplicationTy, CallableDef, GenericPredicate, InEnvironment, OpaqueTy, OpaqueTyId,
ProjectionPredicate, ProjectionTy, Substs, TraitEnvironment, TraitRef, Ty, TypeCtor,
ProjectionPredicate, ProjectionTy, Substs, TraitEnvironment, TraitRef, Ty, TyKind, TypeCtor,
};
use super::interner::*;
@ -555,22 +555,39 @@ where
type Chalk = chalk_ir::Canonical<T::Chalk>;
fn to_chalk(self, db: &dyn HirDatabase) -> chalk_ir::Canonical<T::Chalk> {
let parameter = chalk_ir::CanonicalVarKind::new(
chalk_ir::VariableKind::Ty(chalk_ir::TyKind::General),
chalk_ir::UniverseIndex::ROOT,
);
let kinds = self
.kinds
.iter()
.map(|k| match k {
TyKind::General => chalk_ir::TyKind::General,
TyKind::Integer => chalk_ir::TyKind::Integer,
TyKind::Float => chalk_ir::TyKind::Float,
})
.map(|tk| {
chalk_ir::CanonicalVarKind::new(
chalk_ir::VariableKind::Ty(tk),
chalk_ir::UniverseIndex::ROOT,
)
});
let value = self.value.to_chalk(db);
chalk_ir::Canonical {
value,
binders: chalk_ir::CanonicalVarKinds::from(&Interner, vec![parameter; self.num_vars]),
}
chalk_ir::Canonical { value, binders: chalk_ir::CanonicalVarKinds::from(&Interner, kinds) }
}
fn from_chalk(db: &dyn HirDatabase, canonical: chalk_ir::Canonical<T::Chalk>) -> Canonical<T> {
Canonical {
num_vars: canonical.binders.len(&Interner),
value: from_chalk(db, canonical.value),
}
let kinds = canonical
.binders
.iter(&Interner)
.map(|k| match k.kind {
chalk_ir::VariableKind::Ty(tk) => match tk {
chalk_ir::TyKind::General => TyKind::General,
chalk_ir::TyKind::Integer => TyKind::Integer,
chalk_ir::TyKind::Float => TyKind::Float,
},
chalk_ir::VariableKind::Lifetime => panic!("unexpected lifetime from Chalk"),
chalk_ir::VariableKind::Const(_) => panic!("unexpected const from Chalk"),
})
.collect();
Canonical { kinds, value: from_chalk(db, canonical.value) }
}
}